Numerical and Experimental Studies of Sand-Clay Interface

Abstract

A recent experimental work of Frikha et al. (2015) demonstrated that when the number of granular columns increases at a fixed area replacement ratio “η”, the contact surface between the reinforcing columns and the clayey soil increases and results in an increase in the soil-column interface friction, which enhances the strength properties of the reinforced soft clayey soil. Granular Columns/soil interface strength can play then an important role in the bearing capacity of reinforced soil. However, it would appear that none of the methods proposed of design of granular column to date are able to reliably predict performance to a satisfactory level of accuracy due to the intrinsic characteristics of interface properties Columns/soil.

The present paper try to carry out into the shear behavior of sand/clayey soil interface using a simple direct shear test. In the shear test a shearing surface is produced and the resistance to shearing is defined as the shear resistance. The frictional resistance is, however, determined on an existing joint surface. The frictional behavior at the soil – other materials interface is usually and commonly obtained from direct shear tests. A numerical modelling analysis of direct shearing box test using FLAC3D was performed in order to define the interface parameter by comparing the experimental results with the numerical one. The principal purpose of this work is to define the properties of the interface for a future numerical simulation of behavior of clayey soil reinforced by granular column.